AS Edexcel Chemistry- New Spec Units 1 & 2 2009

Scroll to see replies

VANILLA.BEAR

I thought that reading this would help... but it's actually made me feel worse about these sodding chemistry exams- everyone here seems to know a hell of a lot compared to the very little I know...

Meh. I may as well give up now.

:frown:

Don't give up :smile:

I feel like there's a ton of stuff I don't know, but we still have 9 days. Hardcore revision to come :yep:

Reply 81

chuck111

Pinapse The Synapse

Hi everyone, I'm not looking forward to these exams at all! :cry:

And... um, how do CFCs put out fires?

umm they put out fires becuase the C-F bond is strong. They form a heavy blanket layer excluding oxygen therefore the fire cant burn as it has limited oxygen and to burn the fire needs oxygen.....I hope this is right help me out draconis ahha lol

Reply 82

Draconis

Then hopefully the pressure will make you study even harder for Chem. :yep:

I'm doing the same subjects as you btw. :cool:

Reply 83

Draconis

chuck111

Hehe I'm saving all that stuff for the weekend, otherwise it just won't stick until the exam. But that's what I thought when I read the question too.

Reply 84

anyarian

i did well in jan unit 1, got 115/120.
but unit 2 is harder, and it seems like there's loads more of it!
plus that week is horrible for me: the monday i have bio unit 2, tuesday i have history, wednesday i have chemistry in the morning, and then 2 latin exams in the afternoon. horrible!

Reply 85

VANILLA.BEAR

Draconis

Don't give up :smile:

I feel like there's a ton of stuff I don't know, but we still have 9 days. Hardcore revision to come :yep:

If I didn't have 2 biology exams, and a freaking mechanics exam- both of which I have barely revised for- I wouldn't be feeling so negative.
:frown:

Ah well, guess it's my fault for letting it pile up.

Reply 86

Draconis

VANILLA.BEAR

If I didn't have 2 biology exams, and a freaking mechanics exam- both of which I have barely revised for- I wouldn't be feeling so negative.
:frown:

Ah well, guess it's my fault for letting it pile up.

You've still got time, and a whole week off school :smile:

Reply 87

chuck111

anyarian

umm ar yu doing ocr biology?? if you are omfg the biodiversity stuff is like so bad....shoot me now

I swear my brain is going to explode with so much info going in at once lol im planning on doing all nighters every night this week and then waking up around 12pm

Reply 88

chuck111

C'mon guys at least you've landed on this thread and its most likely gunna giv u a kick up the backside so lets not be so pesimistic :biggrin:

im such a hypocrite :P

Reply 89

Draconis

Does anybody know if we need to know about herbicides and pesticides in relation to CFCs?

Reply 90

ADaniels92

******...***** This book is mad! Or I am...

According to my notes and two people on here (Chuck and Draconis, thanks btw) in an ionic bond when the cation polarises the anion it distorts the bond and weakens it right? It can also be said that this distortion of the bond is creating covalent character, right? If this is true then wtf is this:

" AgCl:

Born-Haber Lattice energy = -905
Theoretical Lattice energy = -833

This suggests that the silver halides are more stable than a purely ionic model indicates. In other words, they show a considerable degree of covalent character."

I can see what they're saying though, from those figures it shows that covalent character which is clearly occuring in the ionic compound is accounted for in the Born-Haber figure, whereas it is not in the theoretical figure. As a result the figure which accounts for this covalent character is shown to be more stable...

So confused!

Reply 91

chuck111

Draconis

Does anybody know if we need to know about herbicides and pesticides in relation to CFCs?

umm i dunno lol im gunan revise tht now umm all I can find is stuff on refridgerants,anaesthesia and fire retardants.

Reply 92

Draconis

ADaniels92

Note that they're talking about silver halides. The stability we're talking about in unit 2 is group 2 carbonates and nitrates.

EDIT: It is confusing, I will try to find a definite answer.

Reply 93

ADaniels92

Thanks again. I see your point maybe I just need to separate the two ideas, not try to combine them... I suppose they will be on different papers after all...

Reply 94

JoshFlack

anyarian

I know how you feel. I have Biology, History and then Chemistry. Don't have Latin, but then on the Friday I have Physics 2 and then two maths papers. Not cool. Luckily i got 120 UMS on unit 1 :smile:

Reply 95

MCR-ROCK-MY-SOCKS-OFF

LaRgEgIrL

Glad people like the thread!

My school didn't allow it either, I sat it outside of school as well as S1.

Chemistry was such a Failure!

I think I got 87/120 -UMS
S1 went a lot better though! :biggrin:

91/100

The topics I'm struggling with are Further Organic & Infrared Spectroscopy

xxx

omg i hate infrared spectrscopy AND green chemistry thrye long and i dont understand what we need to know exactly!! :mad:

plus any1 know what the context studies are for (the handouts that are for spectroscopy,green chemistry and i think the 3rd one is on the enviroment) what r they for and do we need to learn them??????????????

Reply 96

Survivor007

how the hell do you guys get 120/120 and 115/120 omg thaT is just not normal ,do you guys revise like 24/7

Reply 97

Draconis

ADaniels92

Thanks again. I see your point maybe I just need to separate the two ideas, not try to combine them... I suppose they will be on different papers after all...

I think you'll be quite pleased with this answer. :p:

Say you have MgCO₃. You want to decompose it. The molecule is polarised so that the Mg ion is bonded to an oxygen in CO₃. This means that the electrons in one of the oxygen atoms are more drawn to the Mg ion than to the carbon atom in the molecule. The product you get when decomposing a carbonate is CO₂. Since the MgO part of the molecule has covalent character, it is easier for the CO₂ part to break off.

Make sense?

Reply 98

Draconis

Survivor007

how the hell do you guys get 120/120 and 115/120 omg thaT is just not normal ,do you guys revise like 24/7

Not really. I like the subject and it comes quite naturally to me. I'd have to revise 24/7 for subjects such as Geography and History, because I don't have a natural inclination to it.

Reply 99

chuck111

Draconis

Note that they're talking about silver halides. The stability we're talking about in unit 2 is group 2 carbonates and nitrates.

EDIT: It is confusing, I will try to find a definite answer.